A display device is arranged with a light emitting element in each pixel and displays an image by individually controlling emitted light. For example, in an organic EL display device using an organic EL element as a light emitting element, an organic EL element is arranged in each pixel and the organic EL element has a structure in which a layer including an organic EL material (referred to herein as [organic EL layer]) is sandwiched between a pair of electrodes comprised from an anode electrode and a cathode electrode. An organic EL display device is arranged with the anode electrode as an individual pixel electrode in each pixel, and the cathode electrode is arranged bridging a plurality of pixel as a common pixel electrode applied with a common potential. The organic EL display device controls light emitted from a pixel by applying the voltage of a pixel electrode to each pixel with respect to the potential of the common pixel electrode.
An organic EL layer is extremely weak to water and when water infiltrates from the exterior to the interior of a panel and reaches the organic EL layer, non-lighting regions called dark spots may be produced. Thus, in order to prevent water infiltrating to an organic EL layer, a measure has been adopted for forming a sealing film to cover a structure of a display region arranged with an organic EL element.
A structure in which mainly an organic insulation film, and a side surface and upper and lower surfaces of the organic insulation film are stacked with an inorganic insulation film is generally used as a sealing film. In order to prevent the infiltration of water in a side surface direction, it is necessary to seal an end part of a region arranged with the organic insulation film using the upper and lower surface inorganic insulation film. Enclosing a region for arranging an organic insulation film by a dam part and damming the organic insulation film on an inner side of the dam part as a method for determining the position of an end part is disclosed in Japanese Laid Open Patent Publication No. 2008-165251.
However, it has become necessary to significantly narrow a display region outer periphery part together with the narrowing of a frame in recent years and it has become increasingly difficult to control the position of an end part of an organic insulation film.